Field of the Invention
The present invention relates to a technique of controlling jobs to be performed by a plurality of image forming devices under the management of a server.
Description of the Related Art
In an office environment, as routine work, an instruction to print document data is given from a PC to an image forming device such as a Multi Function Printer (MFP) in order to perform printing in an environment in which the PC and the image forming device are connected via a network. In recent years, there is a growing tendency to save power and, in office work, there is also a need to save energy.
FIG. 1 is a graph showing a relationship between power consumption and elapsed time in performing a plurality of types of jobs with one MFP. The vertical axis of the graph shows the power consumption of a controller of the image forming device, and the lateral axis shows the elapsed time. As is understood from the graph of FIG. 1, power consumption for a copy job and a print job is far higher than power consumption for any other processing (such as processing for a scan job or sleep processing).
FIG. 2 is a graph showing a relationship between power consumption and elapsed time in performing print jobs simultaneously with two MFPs. It is found from the graph of FIG. 2 that in a case where the two MFPs simultaneously perform print jobs whose power consumption is high, the total power consumption of the controller is sharply increased. This means that maximum power consumption in an office environment is increased greatly. In order to save energy, it is important to reduce maximum power consumption.
From this viewpoint, in the case of using a plurality of MFPs, it is conceivable to perform control so that after a first MFP completes a print job, a second MFP performs a print job (sequential control). FIG. 3 is a graph showing a relationship between power consumption and elapsed time in a case where control is performed so that two MFPs sequentially perform print jobs. Maximum power consumption can be reduced by performing control in the above manner.
However, in a case where control is performed in the above manner to prevent the plurality of print jobs from being overlapped with each other, the second job does not start until the first job ends. This makes it time-consuming to perform the jobs and reduces work efficiency. Further, Japanese Patent Laid-Open No. 2003-299264 and No. 2002-142385 proposes a technique of controlling power by measuring the amount of a rush current of a device and the amount of power of a whole system. However, devices for the measurements and the like are necessary, and the cost becomes high.
Further, besides a print function, an MFP has various functions such as a copy function, a SEND function (a function for scanning a manuscript and transferring resultant electronic data), and a FAX transmission/reception function. Accordingly, it is necessary to perform comprehensive control for processing these jobs. For example, in a case where printing is being performed, a user has to wait at an MFP for a copy job or a FAX transmission job instructed by an operation unit of an MFP body until the print job ends and mere sequential control may result in significant reduction in work efficiency. Accordingly, efficient processing for jobs other than a print job is also required to be attained.